Computer readable storage medium for multi-language debugging

ABSTRACT

Software developers working on multi-language systems can utilize a multi-language debugging environment. The debugging environment can be uniform across languages, and can seamlessly perform debugging between one or more languages in a multi-language environment. Such a system can have a number of attributes intended to help developers facing debugging problems in multi-language environments. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No. 10/784,600 entitled “Method for Multi-Language Debugging,” filed on Feb. 23, 2004 by William A. Pugh, et al., which claims priority to U.S. Provisional Application No. 60/450,014 entitled “Systems and Methods for Multi-Language Debugging,” filed on Feb. 26, 2003, by William A. Pugh, et al., which applications are incorporated by reference.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document of the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

FIELD OF THE INVENTION

The present invention relates to the debugging of software and software components.

BACKGROUND

Most real-world software systems of any significant complexity are written in more than one programming language. For example, an environment may be implemented in JAVA™ while an interpreted language may be running on top of JAVA™ and need to be debugged. This situation creates significant difficulties for software developers attempting to debug these systems. This problem is complicated by the fact that there is no standardization in terms of internal structures, such as stack frames, between different programming languages. For example, it is not uncommon for a developer to see stack information not directly related to the software being debugged when encountering a stack frame for one language, when using a debugger intended for another language. As another example, when using a debugger intended for the JAVA™ language, a JAVA™ stack will not include the stack for XScript (a JavaScript variant with native support for extensible markup language (XML)), and can sometimes show the set of Java classes that implement the XScript engine (these are part of the environment, but not the software the developer is working on). One multi-language debugger, described in JAVA™ Specification Request (JSR) 45, can only be used to debug languages that are easily transformed into Java and then compiled. This and most other multi-language debuggers won't work with languages such as XScript where the language will be run by an interpreter or the language can not be mapped directly to JAVA™ because the language has a different data structure. Thus, creating debugging tools that can be applied to software applied to more than one programming language, and running in the same environment, has proved to be extremely difficult.

SUMMARY OF THE INVENTION

Methods for a debugging environment that can be used by software developers working on multi-language systems. The techniques used create a debugging environment that can be uniform across languages, and can seamlessly perform debugging between one or more languages in a multi-language environment. Such a system can have a number of attributes intended to help developers facing debugging problems in multi-language environments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 describes an initialization process for one embodiment of the invention.

DETAILED DESCRIPTION

Systems and methods in accordance with embodiments of the present invention provide a debugging environment that can be used by software developers working on multi-language systems. The techniques used create a debugging environment that can be uniform across languages, and can seamlessly perform debugging between one or more languages in a multi-language environment. Such a system can have a number of attributes intended to help developers facing debugging problems in multi-language environments including:

-   -   Integrate debugging between two or more languages at the same         time. If more than one language appears on a stack, a developer         can see the frames for each language, as well as be able to         inspect variables for each language.     -   Nested language debugging. A developer can debug source code         that has several nested languages within a single source file.         Mixing several languages in a single source file is becoming an         increasingly valuable and popular capability. For example, the         emerging ECMAScript for XML languages embeds the XML languages         directly in ECMAScript.     -   An extensible architecture. Support for additional languages can         be added to the multi-language debugging environment. For         example, using multiple language definitions, a developer can         perform debugging in the JAVA™ language, Xscript language, the         Xquery language, and various Business Process Modeling         languages, such as the Business Process Execution Language.

Each language integrated into a multi-language debugger can include specific support for the stack frame structures and variable representations used in that language. Each new language added to the multi-language debugger can extend the system in at least one of 3 areas:

-   -   The Integrated Development Environment (IDE). If the debugger is         associated with an IDE, this environment can contain support for         the languages supported by the debugger. These extensions may         include appropriate APIs to get at dialog boxes (watch, locals,         stack frame, etc), as well as the debugging commands. As an         example, many Business Processes Modeling languages will simply         be extensions in the IDE that will map to normal JAVA™ code, or         code in some other complied or interpreted programming language.         In these cases, the extensions may be able to simply create         extensions to the IDE environment for the underling programming         language.     -   The Proxy. In one embodiment of the present invention, the proxy         is not required. When implemented, the proxy may be used to         implement user interface (UI) commands into the underlying         debugging framework requests. The proxy can be used in-process         or out-of-process. In the case where a proxy is out-of-process         and used as an intermediate between the environment the software         is executing in and the debugger, a proxy with the correct         mapping between the new language and the underling language may         be used. For example, to add debugging for a new language that         maps directly to JAVA™ byte codes, the proxy is extended to map         between the new language and JAVA™.     -   Runtime messaging infrastructure. For some languages the         debugger should be capable of interacting with the messaging         infrastructure. For example, to debug an interpreted language,         like Xscript, the debugging may be done on the server side of         the messaging infrastructure. In one embodiment, the Runtime         messaging infrastructure may interpret language interactions and         perform debugging in JAVA™ Platform Debugging Architecture         (JPDA).

Throughout the following discussion, an example is developed using the JAVA™ language. It will be understood that the invention is equally applicable to any programming language. This example is presented for illustrative purposes only and is not meant to limit the scope, functionality or spirit of any particular embodiment of the invention.

Architectural Overview

Some embodiments will be comprised of one or more functional components or modules. It will be understood that any particular embodiment of the invention may not require all of the components listed, may use additional components, or may use an entirely different organization without changing the functionality, scope or spirit. Components used in some embodiments can include:

-   -   A proxy—In some embodiments a proxy is used between the         executing code being debugged and the debugger. In some cases,         the proxy serves to improve the efficiency or reduce the         overhead associated with debugging protocols. For example, many         JAVA™ language debuggers use the JAVA™ Debugging Interface         (JDI), which has a fine-grain API and therefore will create a         lot of message traffic between the code under test and the         debugger. In this case a proxy can consolidate the contents of         some of the messages, potentially reducing messages and         overhead.     -   A script engine interface—A script engine can communicate with         the multi- language debugger through a standardized interface.         This interface can be used by the multi-language debugger to         communicate metadata to the proxy (or possibly directly to the         debugger), so the proxy can determine when to call into which         debuggable language. As an example, for multi-language support         of JavaScript, a JAVA™ language debugger may define an         interface, possibly called IdebuggableLanguage, which is used         anytime the script engine is invoked. Typically there is an         object in the JAVA™ stack that implements this interface, and         can translate the JAVA™ stack into a JavaScript stack.     -   A debuggable frame—For each language supported, the scripting         engine may use a debuggable frame object, capable of retrieving         the script context. As an example, a JAVA™ language debugger may         define such a standardized frame, possibly known as         IdebuggableFrame.     -   An interface to the messaging environment—This is an interface         that can be implemented by a runtime-messaging environment that         controls the running state of the scripting engines. As an         example, a JAVA™ language debugger may define a standardized         interface, possibly known as IdebugScriptController.     -   Script context object—For each language supported, the scripting         engine can use an object to hold a script context. As an         example, a JAVA™ language debugger may define a standardized         object, possibly known as IcontextHolder.     -   A debug commands interface—For each language supported, the         script engine can use a standardized interface, which the         multi-language debugger uses to call into the different         debuggable languages. As an example, a JAVA™ language debugger         may define a standardized object, possibly known as         IDebugCommands.     -   A script debug controller—A script engine may have a static         constructor that loads a script debug controller, which may         registers itself upon start-up. When the script engine registers         itself, the script debug controller may get the following         information from the engine: a) the language extensions for each         language, b) the classes that implement the script engine, c)         information on optional capabilities for the language, and d)         the language name. In some cases the controller may store this         information internally in a map that goes from extension to         script engine. As an example, for a JAVA™ language debugger the         script debug controller, possibly known as         ScriptDebugController, is defined in debugger.jar.         Process Overview

In some embodiments, when the runtime-messaging infrastructure is started in non-production (debug) mode, a script controller for the debug process is started. This object inspects the system for script engines, and loads them and their configuration information.

In some embodiments when the runtime-messaging infrastructure starts a debugging session, it will send a message to the proxy. Typically, this message includes a list of languages and language configuration information for the languages supported by the multi-language debugger. In some embodiments, when debugging begins, the debug proxy will talk to the script controller for control flow (e.g. step, continue, pause), and will operate directly on the script engines for debugging information (e.g. stack frames, variable inspection, expressions).

In some embodiments, after the script engines have all registered themselves, the script debug controller waits until debugging is started. This process is depicted in FIG. 1. Once debugging commences:

1. The server can send 102 an initialization message to the proxy.

2. The proxy can respond 104 with a packet indicating the languages discovered.

3. The server can send 106 a language response packet during the boot sequence. This packet may include the information used by the script debug controller, such as: a) the language extensions for each language, b) the classes that implement the script engine, c) information on optional capabilities for the language, and d) the language name.

4. The proxy will now send 108 a message indicating the successful completion of the initialization to the runtime massaging server, and will then wait for events.

Breakpoint Hits

In some embodiments, when a breakpoint is hit, or a step is finished in communications with the script engine will be to the script debug controller. As an example, with JAVA™ code, all communications with the script engines will be through JDI calls to the script debug controller.

For some embodiments, the first breakpoint hit in the underling language can behave like a normal break. The following process may then occur:

1. The debugger gets the current class, line, and stack and processes the stack through a language filter. If during processing, the debugger encounters a class that implements a script language the following steps may be take: a) if the object derives from a context holder, the debug script controller makes a method call to get the context, and b) the debug script controller will call a method to get the contents of the stack. Continuing the examples for the JAVA™ language, the debug script controller will call getcontext (or some other suitable named method) on the IcontextHolder object to get the context and then calls a method ScriptDebugController.getStack (LanguageExt, Context) (or some other suitable named method) via JDI, to get a list of scriptFrames.

2. All script languages are processed as described above, creating a stack frame list to send back to the debugger.

3. The debugger proceeds to discover and inspect variables in the same way as before.

Current Frame Set to Script Frame

In some embodiments, the following process may occur if the current stack frame is set to a frame controlled by a script engine:

-   1. Get the “this” object and the frame variables and send them to     the client as the list of variables.

2. For each object queried, call a method to get the values of the script variables. Continuing the example for the JAVA™ language, a call is made to IDebuggableLanguage.getVariable( ) (or some other suitable named method), to get the IScriptVariable (or some other suitable named interface)value. Some possible Java language examples of the results of this operation can be seen in the following table. Value Value Type Type Display Display If Expanded In Expression Simple getValue( ) getType( ) — Call getPrimativeType( ) to determine which get* function to call to get the correct value. Complex getValue( ) Get Call Use getMember to get members, Type getMembers( ) to and callMethod to call methods on ( ) get the list of the value. members to display, then call getMember( ) one each to get the values. Array getValue( ) getType( ) Create a list Use getElement to lookup the getLength( ) long, values and populate it with calls to getElement( ) Other Call into the Call into the Call into the Call into the Language ScriptDebug ScriptDebug ScriptDebugController ScriptDebugController to get a Controller to Controller to to get a resolved ScriptValue and use that. get a get a resolved resolved resolved ScriptValue and ScriptValue ScriptValue use that. and use and use that. that. Java Call Call Call Call getValueObject and treat as getValueObject getValueObject getValueObject ordinary Java Object and treat as and treat as and treat as ordinary ordinary ordinary Java Java Object Java Object Object Stepping Through Code

Some embodiments can step though code using a mechanism analogous to that used in an ordinary (without multi-language support) debugger, except that the debugger will inform the script debug controller when a step is about to begin. In this way, any script engine that is started, and script engines that return from calling into the underling language (e.g. JAVA™) will be able to stop appropriately. In some cases, script implementation classes are placed into the excludes-filter during a step request.

Continuing

In some embodiments this operation behaves like a continue in an ordinary (not multi-language) debugger.

Script Breakpoint Hit

In some embodiments, when a script breakpoint is hit the following actions can occur:

-   -   The script controller will call a breakpoint method, sending a         message indicating the breakpoint hit to the proxy. Continuing         the JAVA™ language example, the controller can call into a         method with a name, such as, ScriptDebugController.Break( ) to         send the message to the proxy.     -   The Proxy can then freeze the thread, and perform any required         communications. In the JAVA™ example these communications can         use function calls via JDI.     -   When the user decides to continue, the debugger will unfreeze         the thread and send a Continue, StepIn, StepOver, StepOut, etc.,         packet as appropriate.         In some embodiments, if the user hits Stop instead of Continue,         the thread can be un- frozen, no network packet will be sent,         and the thread may be forced to throw an exception used for         killing threads. Alternatively, such actions by the user can be         temporarily blocked.         Pause

In some embodiments, when the user hits Pause, the thread will be paused. The debugger can then look to see if the stack is currently in scripting or the underling language (e.g. JAVA™) code. One of the following actions may then be taken:

-   1. If the stack is in the underling language code, the process is     complete. In some cases, this situation is treated in the same way     hitting a breakpoint is treated. -   2. If the stack is in script code, a pause method is called on the     script engine interface and the execution of the scripting language     will continue until it hits a stopping point, when a pause method is     called on the script debug controller. Continuing the JAVA™ language     example, when a pause( ) method on the IdebuggableLanguage interface     is called, the scripting language will continue until it hits a     stopping point, at which point the engine calls     ScriptDebugController.Pause( ).     In some embodiments, when a pause is called on a script language     while it is waiting on some synchronization object, it will be     treated as a normal thread in the underling language (e.g. JAVA™),     which can prevent deadlock scenarios.     Breakpoints

In some embodiments, information in breakpoint packets can use a suitable extension or other indicator to identify the language type being executed. In some cases, the absence of the extension can indicate the underling language (e.g. JAVA™) is being used. If a breakpoint is not in the underling language the following actions may be taken:

-   1. Send a message to the script debug controller telling it to set a     breakpoint. -   2. The script debug controller will look up the proper extension or     indicator and set a breakpoint using the method available for that     language. -   3. The script debug controller will then send a message indicating     the success or failure of setting the breakpoint.

In some embodiments several types of breakpoints are supported, which can include: Source Breakpoints This is the ordinary type of breakpoint that goes on a source file/line number Method Breakpoint This breakpoint is hit when a certain method is called Watch point This breakpoint is hit when a variable is either read or written.

It should be noted, that depending on the details of the embodiment, any language may be able to support a sub-set of the available breakpoint types for any given language. Returning a true or false to a query for that type can indicate the support for a particular breakpoint type. For example, a true or false can be returned for a method, featureEnabledo (or some other suitable name), when called with a variable indicating the break point type, such as, SOURCE_BREAKPOINT_SUPPORT, METHOD_BREAKPOINT_SUPPORT, or WATCH_POINT_SUPPORT

An Example Interfaces

The following examples show sets of interface definitions for two embodiments, developed using the JAVA™ language. It will be understood that the invention is equally applicable to any programming language. This example is presented for illustrative purposes only and is not meant to limit the scope, functionality or spirit of any particular embodiment of the invention.

Network Messages

As has already been discussed, some embodiments use facilities in the runtime-messaging environment to perform debugging operations on network messages. This capability is demonstrated here by example shown in the table below developed using the JAVA™ language. In another embodiment, method calls may be made via the native debugging infrastructure JDI. Methods are called on the ScriptController via JDI to do continues and other such tasks. Breakpoints are executed by hitting actual Java breakpoint and are then translated in the proxy to script breakpoint. Thus, breakpoints reduce to java breakpoints. JDI sends a message to the proxy in the underlying JDI protocol. For example, a packet may be sent from the server to the proxy that includes meta-data for a scripting language. The meta-data is used to determine whether to treat the language as a scripting language or to treat the language as a native language. It will be understood that the invention is equally applicable to any programming language. This example is presented for illustrative purposes only and is not meant to limit the scope, functionality or spirit of any particular embodiment of the invention. Message Sender Meaning Parameters SetBreakpoint Proxy Trying to set a File - File name script breakpoint. Line - Line number Language Ext - Language Extension SetMethodBreakpoint Proxy Trying to set a Class - Class name (or file name breakpoint on a is language doesn't have classes) method Method -- Name of the method to set a breakpoint on Parameters - The parameters for the method to set a breakpoint on. This disambiguates in the case of multiple methods with the same name but different parameters Language Ext - Language Extensions BreakpointSet Runtime- Breakpoint is set Status - Did the breakpoint get set messaging Error -- Error message if it failed environment BreakHit Runtime- A Script hit a File - the file name messaging breakpoint Line - the line number environment Continue Proxy A script should ContinueType - whether this resume should continue with a step or a continue Pause Runtime- Tells the proxy a PauseID - This is the ID we use messaging script has gotten to map a pause the thread it was environment to a safe place requested on. and paused

The foregoing description of preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to one of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. 

1. A computer-readable storage medium, with instructions stored thereon for debugging in more than one programming language with a multi-language debugger, comprising: debugging a source code file which contains multiple nested languages; interpreting multiple nested languages within a single source file and displaying each of the multiple nested languages in a debugging frame; editing each language in a debugging frame; and wherein the multi-language debugger uses a standardize interface for a script engine and all communications with the script engine will be through calls to a script debug controller.
 2. The computer-readable storage medium of claim 1, wherein the multi-language debugger is extensible and a user can add language definitions to support additional languages.
 3. The computer-readable storage medium of claim 1, wherein if more than one language appears on a stack, a user can see a debuggable frame for each language and the user can inspect variables for each language.
 4. The computer-readable storage medium of claim 1, wherein a proxy is used between executing code being debugged and a debugger.
 5. The computer-readable storage medium of claim 1, wherein a script engine interface can be used by a debugger to communicate metadata to a proxy.
 6. The computer-readable storage medium of claim 1, wherein a debugger interacts with a runtime messaging environment.
 7. The computer-readable storage medium of claim 1, wherein debugging is performed on a server side of a runtime messaging environment.
 8. The computer-readable storage medium of claim 1, wherein a runtime messaging environment interprets language interactions and performs debugging.
 9. The computer-readable storage medium of claim 1, wherein a script engine has a static constructor load a script debug controller.
 10. The computer-readable storage medium of claim 9, wherein the script debug controller receives information from the script engine, comprising: a) language extensions for each language; b) classes that implement the script engine; c) information on optional capabilities for each language; and d) language name. 